Antibiotics able to trick the bacteria that build drug immunity have shown promising results in laboratory testing.

Researchers at Adelaide University, working in collaboration with Monash University and Adelaide's Women's and Children's Hospital, have developed a way of stopping the growth of key proteins.

"It's still early stage research, but what we've done is identify the fact that, as many others have, there's a need for new classes of antibiotics, ones that have a novel mode of action so that way it can combat the problems of resistance with common antibiotics these days," project leader Professor Andrew Abell explained.

"We've identified a key biological target within the bacteria and, if you can knock out that target, then the bacteria can't survive.

"It's a protein target that no one else has targeted before so as a consequence the compounds and the approach are quite new."

The protein is known as biotin protein ligase and Professor Abell explained that without it bacteria cannot survive.

"It's a critical part of lots of key processes within the life cycle," he said.

"It's also found in humans, so we also have the same protein.

"What we've had to do is to design small molecules to bind specifically to the bacterial form and not the human form, because clearly it wouldn't be much use it if also killed the human."

Golden staph and TB tackled

Professor Abell and his team have tackled deadly golden staph, but also recently turned their attention to tuberculosis.

"This protein is found in all of these proteins, so we can tailor our small molecule to bind to the TB form or to the golden staph form," he said.

Professor Abell said the molecule structure could be tweaked to tackle various diseases.

"Think of it like a lock and a key," he said. "If the lock was the protein, the key is the small molecule that fits in that lock.

"We've identified this protein target and then we study this protein target and we can get a three-dimensional picture of it and then we can specifically, or selectively, design a small molecule that will bind to it.

"We get the bacterial protein, we give it a library of these small molecules and it actually chooses the one that binds best to the protein, so unwittingly it's sort of chooses the one that's the most potent structure, so we're using the target itself to find the most potent small molecule inhibitor of this protein."

Professor Abell said similar work had been done but not to the extent of engineering particular proteins to perform the process better.

"What we've done so far is shown that these molecules inhibit the protein, so you can do that in a test tube-type experiment," he said.

"What we've also shown is that these compounds stop the growth of these bacteria effectively in a Petri dish.

"What we've now got to do is to get them into an animal model - a rat or a mouse infection model with the actual bacteria - and hopefully show that these things have some efficacy in a live animal."

He said getting the molecules into a human was at least five years away if the testing went to plan.